Hygienics in the daily life continues to draw more attention as humanities improve. For one, hygienics is particularly valued in public restrooms. To quickly remove residual water from hands after washing hands, paper towels for wiping hands are usually offered in public restrooms. However, such paper towels that are disposed after one-time use do not meet green requirements of the world today. As a result, hand dryers that can be used to replace paper towels are widely provided in public restrooms.
With the progress of infrared sensors, technologies for driving a hand dryer through sensing hands of a user by an infrared sensor have been developed. For example, the Taiwan Patent I326207 discloses “Dehumidified Hand Dryer”. The disclosed hand dryer includes a hand drying device, a dehumidifying device and a temperature control device. The hand drying device includes a hollow casing, a heater, an airflow inlet fan, and an airflow outlet fan. The dehumidifying device includes a first thermoelectric module and a second thermoelectric module. The temperature control device is mounted on the hollow casing, powers the hand drying device and the dehumidifying device, and controls hand drying and temperature control operations in an ambient environment. The temperature control device includes a control circuit board, an infrared sensor, a power switch button, and a forced stop button. When the infrared sensor senses that hands are placed into a lower part of an airflow discharge opening, the airflow inlet fan is activated and the airflow outlet fan starts rotating at a high speed. A heated airflow at an airflow duct is discharged out of the airflow discharge opening to achieve an effect of hand drying. For another example, the U.S. Pat. No. 5,186,360 discloses “Automatic Soap Dispenser and Hand Drying Unit”. In the above patent, the automatic soap dispenser and hand drying unit include a housing. The housing encloses an automatic soap dispenser at an upper portion thereof, and an automatic hand dryer at a lower portion thereof. An infrared sensor is further included at the lower portion of the housing, and is disposed at a vertical wall surface of a front portion of the housing. The airflow discharge opening of the automatic hand dryer is disposed at an angle relative to the infrared sensor, which detects hands of a user and enables the hand dryer to automatically output a hand drying airflow.
The above dehumidifying hand dryer and automatic soap dispenser and hand drying unit disclosed both include a hand dryer installed with an infrared sensor, with however a distance existing between the infrared sensor and the airflow discharge opening of the hand dryer. When a user intuitively places hands near the airflow discharge opening, the infrared sensor offers inadequate sensing capability for sensing the hands of the user due to the abovementioned distance, in a way that the hand dryer is not driven and fails to provide a hand drying airflow. Further, as the hands of the user need to move back and forth near the airflow discharge opening in order to drive the infrared sensor to perform the corresponding sensing operation, the usage such hand dryer is made quite inconvenient.